1.Erin O'Brien, Director of Consumer Credit with Auckland First Bank (AFB), has implemented a 'fast feedback' to keep her informed of the default rate on personal loans at AFB member banks. On each Friday, the default rate is calculated for a sample of 500 personal loans. Last Friday's sample contained 30 defaulted loans. The 90% confidence interval for the population proportion is _________.

Select one:

a.0.043 to 0.077

b.0.039 to 0.081

c.0.028 to 0.060

d.0.046 to 0.074

2.The table t-value associated with the upper 0.5% of the t-distribution and 4 degrees of freedom is _______.

Select one:

a.2.776

b.4.604

c.2.353

d.2.132

3.The table t-value associated with the upper 10% of the t-distribution and 23 degrees of freedom is _______.

Select one:

a.1.714

b.1.321

c.2.069

d.1.319

4.In order to find values in the t- distribution table, you must convert the sample size or sizes to _______.

Select one:

a.degrees of freedom

b.z-values

c.student values

d.population sizes

5.The normal distribution is used to test about a population mean for large samples if the population standard deviation is known. 'Large' is usually defined as _______.

Select one:

a.at least 100

b.at least 12

c.at least 30

d.at least 5% of the population size

6.A researcher wishes to determine the difference in two population means. To do so, she randomly samples 9 items from each population and calculates a 90% confidence interval. The sample from the first population produces a mean of 780 with a standard deviation of 240. The sample from the second population produces a mean of 890 with a standard deviation of 280. Assume that the values are normally distributed in each population. The t value used for this is 1.337.

Select one:

a.True

b.False

7.Assume that two independent random samples of size 100 each are taken from a population that has a variance of 36. The probability that the difference in the sample means is less than 2 is 0.9909.

Select one:

a.True

b.False

8.James Weepu, Human Resources Manager with Auckland First Bank (AFB), is reviewing the employee training programs of AFB branches. He plans to use a 95% confidence interval estimate of mean training time of tellers and is willing to accept an error of 1 hour; previous studies indicated a standard deviation of 2 hours. The sample size should be at least _______.

Select one:

a.68

b.4

c.16

d.34

9.Cameron Sinclair, Information Services Manager with Global Financial Service (GFS), is studying employee use of GFS email for non-business communications. He plans to use a 95% confidence interval estimate of the proportion of messages that are non-business; he will accept a 0.05 error. Previous studies indicate that approximately 30% of employee email is not business related. Cameron should sample _______ messages.

Select one:

a.457

b.12

c.14

d.323

10.A researcher wants to estimate a population proportion with a 90% level of confidence. From previous studies she estimates that the population proportion is no more than .30. The researcher wants the estimate to have an error of no more than .02. The necessary sample size is at least _______.

Select one:

a.298

b.29

c.1421

d.47

11.A researcher wants to estimate the difference in the means of two populations. A random sample of 36 items from the first population results in a sample mean of 430. A random sample of 49 items from the second population results in a sample mean of 460. The population standard deviations are 120 for the first population and 140 for the second population. From this information, a 95% confidence interval for the difference between means of the first population and the second populationis _______.

Select one:

a.-76.53 to 16.53

b.-102.83 to 42.43

c.-87.60 to 27.60

d.-95.90 to 35.90

12.Cameron Sinclair, Information Services Manager with Global Financial Service (GFS), is studying employee use of GFS email for non-business communications. A random sample of 200 messages was selected. Thirty of the messages were not business related. The 95% confidence interval for the population proportion is _________.

Select one:

a.0.108 to 0.192

b.0.153 to 0.247

c.0.091 to 0.209

d.0.101 to 0.199

13.A random sample of 225 items from a population results in 60% possessing a given characteristic. Using this information, the researcher constructs a 99% confidence interval to estimate the population proportion. The resulting confidence interval is _______.

Select one:

a.0.54 to 0.66

b.0.59 to 0.61

c.0.52 to 0.68

d.0.57 to 0.63

14.The weights of aluminium castings produced by a process are normally distributed. A random sample of 5 castings is selected; the sample mean weight is 2.21 kg; and the sample standard deviation is 0.12 kg. The 98% confidence interval for the population mean casting weight is _________.

Select one:

a.1.76 to 2.66

b.2.01 to 2.41

c.1.93 to 2.49

d.2.08 to 2.34

15.The table t-value associated with 8 degrees of freedom and used to calculate a 99% confidence interval is _______.

Select one:

a.3.355

b.2.896

c.1.397

d.1.860